Machine for surface finishing action on materials



E. FREUD 2,420,876

MACHINE FOR SURFACE FINISHING ACTION ON MATERIALS 1 May 20, 1947.

Filed Feb. 7, 1945 INVENTOR ATTORNEY Patentecl May 20, 1947 UNITED STATE MACHINE Fon SURFACE FINISHING MATERIALS ACTION- Ernest Freumflartford, Conn. Application February 7, 1945, Serial No. 576,637

3 Claims. (01. 51-90) ,This' invention relates to the class of devices for finishing highly polished surfaces on material, such as marble, granite, and the like, and

- an object of my invention, among others, is to ob- Figure 2 is a view in vertical section through the same.

I have found that in imparting a final finish to surfaces, particularly different kinds of stone, as granite, marble and the like, the best results are obtained ifa highly abrasive material, such as Carborundum, is employed and which should be applied at a high rate of speed of the device for making the application as this will produce what may be termed a combined abrasive, cutting, butting, and polishing effect. Such a machine is shown in the accompanying drawings in which the device is supported by an arm 5 pivotally attached to a standard or post of any suitable construction sufficient to enable the arm to have a pivotal action around said support, such support not being shown herein. A shaft 6 is rotatably mounted in the arm 5 and has a pulley I to receive a, belt 8 extending from any suitable source of power which maybe supported by the post hereinbefore mentioned and in a manner that will be readily understood. The structure thus described is that of a well-known and standard granite polishing unit in which arm 5 is pivotally mounted (notshown) to thereby permit a dirigible effect to the polishing unit carried by the arm. In such structures the arm 8a shown in Fig. 2, serves as a, convenient element, readily accessible to the workman, for moving arm 5 on its dirigible pivot, carrying with it the polishing unit which is carried by the end zone of the arm and driven from the power source through belt 8, pulley 1 and shaft 6.

A red 9 extends downwardly from the arm 5 and, supports a bevel gear III of large diameter as compared with the other parts of the machine. The shaft 6 has one member ll of a universal joint secured thereto, the handle 8a being journaled thereon and a second member I2 of said in transverse directions.

Joint is pivotally attached to said first member, the pivotal connection of said members being A shank l3 extending from the member I2 of the universal joint rigidly supports a plate ll upon which a plurality of connecting shafts l5 (four in the present instance) are journaled, each of these shafts mounting a bevel pinion l6 secured to an abrasive wheel ll coated with an abrasive, preferably Carborundum.

As indicated in Fig. 2, the diameter of gear III is many times that of the gears Hi; In practice, I prefer to make the ratio between gear in and gears l8 approximately 10:1 so far as the R. P. M. of shaft 6 and that of gears I6 is concerned;

,since gear I0 is held from rotation by the arm 9,

the planetary movements of the abrasive formations H, as carried by the plate l4, will produce such ratio as the gears l8 traverse gear I0. I have found that with such ratio, a rotation of shaft 6 at 200 R. P.-M., will produce a rotation of gears l6 at about2000 R. P. M.; if the speed of shaft 6 be speeded up while that of gears I6 is unchanged or reduced, there is a considerable loss of efficiency in the apparatus, while a reduction in the speed of shaft 6 materially below the 200 R. P. M., tends to create deep unequal grooves on the surface.

These speeds are approximate, and do not represent the actual speed conditions, as will be apparent, by considering the peripheral speeds. For instance, the diameter of gear III is such as to locate formations ll a considerable distance from the axis of rotation of plate It; hence, the distance of advance of formation ll per unit of time is materially increased, thus permitting the use of the lower speed of shaft 6 and plate l4. Likewise, the diameter of each formation I1 is materially greater than that of its gear 16, so that the peripheral speed of each of the formations I1 is increased in accord with the length of the radius of the formation.

Since the axis of each of the formations I'I v extends horizontally, with the cross-sectional contour of the formation as circular and located tion that tends to simulate the cutting effect proabove the surface being finished, it will be understood that such surface is tangential to the contour of the formation and thuspresents the characteristics of a line contact with the surface at any point of its revolution, and since the outer surface of the formation is preferably formed of Carborundum, it can be understood, that the high peripheral speed of the formation combined with the materially slower advance of the formation in its planetary path, produces an abrading acduced by a milling cutter-in other words, the abrading action in the present invention is of the milling cutting type in which the cutting surface moves at high speed while traversing the work at a materially lower speed, the ratios named indicating somewhat of the effect produced-a materially lower ratio does not produce the result, since a speeding up of the drive shaft to secure the necessary speed for milling cutting by the formation l1, would then set up a very inefiicient planetary speed, while a reduction of the latter to provide efliciency would prevent development of the milling cutting effect of the formations, since the resultant speed is insufiicient to produce such effects.

While the invention is adapted for use in connection with various hard materials, such as metals. granites, hard stones, and the like, the invention is designed more particularly for the finishing of the surfaces of granite, hard stone and similar materials in which the finishing normally is of the polishing type, the machine of the drawings, above the universal Joint ll being a machine of this type, the unit which presents the present invention being readily secured thereto.

The structure is such that by mounting the several parts connecting the driving mechanism with the driven members or abrasive wheels H a very high surface velocity is imparted to said wheels and with such wheels coated with Carborundum an extremely satisfactory finish is imparted to surfaces asstone of different character being finished, and it is found that this high velocity of the surface of the abrasive wheel with the particular abrasive as Carborundum produces results not heretofore attained in machines used for this purpose.

I claim:

1. A surface finishing machine of the character described comprising a supporting arm, a driving shaft rotatable in said arm on a vertical axis, a supporting plate depending from and connected to said shaft by a universal Joint, a plurality of horizontal shafts carried by said supporting plate for rotation on a horizontal axis, a. pinion on each of said horizontal shafts for driving the same, an abrasive wheel said horizontal shafts, a stationary gear co-axial with said supporting plate, and means connecting said gear with said supporting arm to prevent rotation thereof; the said stationary gear being substantially greater in diameter than the pinions on said horizontal shafts for causing rotation of said pinions at a ratio of approximately ten revolutions of said pinions for each revolution of said supporting plate.

' 2. A surface finishing machine of the charac ter described comprising a supporting arm, a driving shaft rotatable in said arm on a vertical axis, a disk carried by said driving shaft and disposed horizontally thereto, a universal joint on each of connected to said shaft and including a member secured to said disk for rotating the same with said shaft, a plurality of horizontal shafts carried by said disk and rotatable thereon on a horizontal axis, each of said horizontal shafts having an abrasive wheel secured thereto and a pinion for rotating said abrasive wheel, a gear of large diameter relatively to said pinions co-axial with said member of the universal joint and in mesh with said pinions, a, connection between said gear and said arm for preventing rotation of the gear, and means for rotating said driving shaft to cause rotation of said disk through said gear by the said member of the universal joint for carrying the abrasive wheel around a vertical axis over a surface being finished while the said wheels are rotated by the pinions as they are carried around the stationary driving gear; the ratio between the drive gear and the pinions being approximately ten to one whereby the said wheels will rotate approximately ten revolutions for each rotation of said drive shaft.

3. A surface finishing machine of the charac-- ter described comprising a supporting arm, a driving shaft rotatable in said arm on a vertical axis, a universal joint comprising a driving member secured to said shaft and a driven member operatively connected with said driving member to swing in a plane transverse thereto, a supporting plate supported by and movable with the said driven member, a large stationary bevel gear co-axial with said driven member of theuniversal joint and carried thereby above said supporting plate, a connection between said bevel gear and supporting arm for preventing rotation of said bevel gear, and a plurality of shafts journaled on said supporting plate for rotation on a horizontal axis; each of said horizontal shafts having an abrasive wheel secured thereto and a pinion in mesh with said large bevel gear.

ERNEST FREUD.

REFERENCES CITED The following references are of record in the I file of this patent:

UNITED STATES PATENTS 

